Earnings (loss) per common share - Summary of computation of basic and diluted earnings (loss) per common share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Numerator:
Net income (loss)	$ 112,281	$ (49,021)	$ (42,652)	$ (39,383)	$ 63,260	$ (82,035)
Denominator:
Weighted average common shares for basic loss per common share	8,750		7,881		8,682	7,416
Effect of dilutive securities	309		0		289	0
Weighted average common shares for diluted loss per common share	9,059		7,881		8,971	7,416
Earnings (loss) per common share, basic	$ 12.83		$ (5.41)		$ 7.29	$ (11.06)
Earnings (loss) per common share, diluted	$ 12.39		$ (5.41)		$ 7.05	$ (11.06)